Compressor unit for refrigeration system



May 1, 1962 A. A. M CORMACK 3,031,861

COMPRESSOR UNIT FOR REFRIGERATION SYSTEM Filed March 13, 1959 6 Sheets-Sheet 1 INVENTOR.

14 EX /4 -Mc Co /mack MM I QWQM flrromwrys y 1, 1962 A. A. M CORMACK 3,031,861

COMPRESSOR UNIT FOR REFRIGERATION SYSTEM Filed March 13, 1959 6 Sheets-Sheet 2 x A. McCoRMAcK 5: 27

Arron/#75 May 1', 1962 A. A. M CORMACK COMPRESSOR UNIT FOR REFRIGERAT Filed March 13, 1959 ION SYSTEM 6 Sheets-Sheet 5 INVENTOR.

ArroRMs-ys y 1962 A. A. M CORMACK 3,031,861

COMPRESSOR UNIT FOR REFRIGERATION SYSTEM Filed March 13. 1959 s Sheets-Sheet 4 INVENTOR.

445x AMcC'oRMncK 7 BYZwQm r A rroxa/vs xs y 1, 1962 I A. A. MQCORMACK 3,031,861

COMPRESSOR UNIT FOR REFRIGERATION SYSTEM Filed March 13, 1959 6 Sheets-Sheet 5 a 66 52 JNVENTOR. k I 70 445x A. McCom mcx flrrore/v gys 3,031,861 CGIVWRESOR UNIT FOR REFRIGERATIGN SYSTEM Alex A. MeCormack, 555 Parkside Drive, Bay Village, Ohio Filed Mar. 13, 1959, Ser. No. 799,338 7 Claims. (Cl. 62-196) This invention relates to compressor units of the kind used in refrigerating and air conditioning apparatus for supplying fluid under pressure to a fluid circuit.

As one of its objects this invention provides a novel compressor unit of this character and embodying a construction of a compact, simplified and highly practical form.

Another object is to provide a sealed and self-lubricating type of compressor unit usable to advantage in compressor-condenser-evaporator fluid circuits and for other purposes, and wherein the pumped fluid is discharged into a body of lubricating liquid contained in the unit, in direct contact with such liquid, to facilitate warm-up of the unit and a better heat dissipation therefrom, as well as to produce'a morerapid separation of the refrigerant from the lubricating oil.

Still another object is to provide a compressor unit having novel valve-controlled bypass means effective to bypass fluid from the discharge side to the intake side of the compressor for various advantageous punposes including that of unloading the compressor upon stopping thereof so as to facilitate restarting of the compressor. The valve-controlled bypass means also produces a novel control action in the'functioning of the unit by which excessive frosting or freeze-up of the evaporator of the associated fluid circuit is prevented.

A further object is to provide a sealed type of compressor unit having a housing comprising-connected sections and containing a compressor and drive motor assembly, and wherein such assembly also serves as an aligning means for the housing sections to facilitate the relative positioning of the latter during the joining thereof.

Still another object is to provide such a sealed type of compressor unit having a lubricant collecting reservoir in the lower'portion of the housing, and wherein the compressor and drive motor assembly includes hollow means located at the lower end thereof and at least partially immersed in the lubricant, such hollow means containing passage means for the fluid being handled by the.

compressor. 7

Additionally, this invention provides a novel construction for a compressor of the rotary type by which different desired volumetric capacity ratings for the compressor are readily obtainable by the use of a minimum number of interchangeable parts.

Other objects and advantages of this invention will be apparent in the following detailed description and in the accompanying drawings forming a part of this specification and in which,

FIG.'1 is a top plan view, with portions broken away, showing a compressor unit embodying this invention;

FIG. 2 is a vertical section taken through the unit substantially on section line 2-2 of FIG. 1;

FIGS. 3 to 7 inclusive are transverse sectional views taken through the unit as indicated by section lines 3-3, 4-4, 5-5, 6--6 and 77 respectively of FIG. 2;

FIGS. 8, 9 and 10 are plan views of a somewhat diagrammatic form and representative of different volumetric capacity ratings obtainable for the compressor in accordance with different combinations of eccentricity values;

FIG. 11 is a diagrammatic view showing the novel compressor unit being used in a compressor-condenserevaporator type of pressure fluid system; and

FIG. 12 is a diagrammatic view similar to that of FIG.

hired tates Patent 0 11 but showing another form of such a pressure fluid system with the novel compressor unit being used therein. As representing a highly practical embodiment of this invention the drawings show a sealed-type of compressor unit 10 adapted for use in a pressure fluid circuit or system, such as a compressor-condenser-evaporator system, and comprising in general a domed housing 11"formed of connected and hermetically sealed upper and lower complemental housing sections 12 and 13, and a pump and driving motor assembly 14 located in the housing.

The housing 11 is provided adjacent the top thereof with a pressure fluid delivery outlet 15 adapted for connection with the supply portion 16 of an external fluid circuit, and is also provided adjacent the lower end thereof with an inlet 17 fitting adapted for connection with the return portion 18 of the external circuit. The assembly 14 is disposed in a substantially coaxial vertical-axis relation in the housing 11 and comprises an electric driving motor 19 and a compressor 20 of the rotary type located immediately below and in a directly connected relation with such driving motor. The compressor 20 is referred to herein merely as a pump for convenience of comparison with the compressor of a conventional sealed-type compressor unit. p v j The housing sections 12 and 13 are here shown as being cup-shaped sections having their adjacent open ends in a connected relation so that the sections define a hermetically sealed main fluid pressure chamber 21 in the housing. The adjacent ends of the housing sections are preferably provided with annular flanges 22 and 23 which are adapted to be welded together, or otherwise suitably connected,

, explained hereinafter.

to provide the hermetically sealed character of the pressure chamber 21. The upper housing section 12 is also provided at the top thereof with a suitable fitting 24 through which electrical conductors 25 are brought into the housing 11 to the electric motor 19 without impairing the hermetically sealed character of the housing.

The lower housing section 13 provides a liquid collecting reservoir 26 in the lower end of the housing 11 which is adapted to contain a body of liquid 27 comprising lubricating oil or a mixture of lubricating oil and refrigerant. The inlet fitting 17 of the lower housing section 13 has a stem portion 28 which extends axially into the housing 11 through a portion of the reservoir 26 and co-operates with the assembly 14 in a manner to be The fitting 17 is connected with the wall of the lower housing section as by a welded connection 29, andcontains an axial passage 30 with which the return portion 18 of the external fluid circuit communicates.

The electric driving motor 19 is of a construction suitable for the type of service for which it is being used and comprises an annular frame member 33 supporting a lam:

inated field ring 34 and suitable field windings 35 in an associated relation to the field ring. The frame member 33 includes an upright central hollow bearing 36 in which a vertical shaft 37 is rotatably journaled. The shaft 37 is secured to an armature 38 which is rotatable in the field ring 34. The shaft is of a length to extend downwardly through the pump 20 as the impeller shaft of the latter.

In accordance with one feature of this invention, the assembly 14-is located in the housing 11 so that the lower end of the assembly extends into the reservoir 26 and is immersed in. the body of liquid 27 for a purpose to be explained hereinafter. The assembly 14 is provided at the lower end thereof with co-operating hollow mufller and cover members 40 and 41 which contain passages and chambers for the fluid being handled by the pump 20 and which passages include a suction passage 42 for supplying intake fluid to the pump and a delivery pas:

sage 43 for receiving the pressure fluid discharge from the pump.

According to another feature of this invention, the assembly 14 is also located in the housing 11 so as to cooperate with the latter as an aligning means for the housing sections 12 and 13. For this purpose the frame member 33 of the driving motor 19 is constructed of a size and shape to tightly engage the wall of the upper housing section 12 when the motor end of the assembly is inserted axially into the latter. As a part of this aligning feature, the muffler cover 4-1 is provided with an axial recess or socket 44 centrally thereof for slidably receiving the stem portion 28 of the fitting 17. v

The stem portion 28 is preferably formed with an enlargement or head 45 thereoncarryinga suitable packing ring 46 and, when the lower housing section 13 is moved into position over the lower end of the assembly 14, the stem 28 enters the recess 44 and the packing ring cooperates with the side wall of the recess to form a sealed connection between the passage 38. and the'inner end of the recess. As the lower housing section 13 is moved into position and the head 45 enters the recess 44, the cooperation of the head with the wall of the recess will cause the lower housing section to be centered and axially I aligned with respect to the upper housing section 12.

When the housing sections are joinedtogether, the connected flanges 22, '23 and the stem 28 will accordingly cause the lower endof the assembly 14 to-be firmly held againstlateral vibration or-shifting in the housing 11.

The peripheral portion of the motor frame 33 is provided at circumferentially. spaced points therearound with axial slots-48 as shown in FIGS. 2 ando. The slots 48 co-operate with the Wall of the housing section 12 to form spaced annular conducting passages for movement of pumped fluid in an upward direction in the housing 11 toward the outlet 15. The slots 48 also permit oil to how downwardly from the upper portion of the unit to the. reservoir 26. The passages provided by the slots 48 are of a size to permit such a return flow of oil simultaneously with the upward flow of pumped fluid therethrough. The pump 24 is best illustrated in FIGS. 2 and 3 and Comprises a pump housing or body 50- having a rotornaled therein. The adapter 56 is itself an eccentric hollow bearing member in that the cylindrical axial opening 57 thereof, in which the shaft eccentric 53 is journaled, is r formed in this member in, an olfset relation as shown. in FIG. 3. The eccentricities of the shaft eccentric 53 and theadapter 56 provide a combined eccentricity or throw, as. will be further explained hereinafter, for producing the gyratory movement of the impeller 52in a manner so that a point of tangency 58 between the periphery of the impeller and the inner annular wall 59 of the cylinder 51 will be maintained and will travel annularly around such inner wall during the gyratory movement. The axis of the shaft 37 is designated by the reference numeral 60 and is the rotation axis of the assembly 14.

The impeller 52 also includes a vane-type abutment blade 61 suitably secured in a radial slot 62 of the ring 54 and projecting into a clearance recess 63' of the pump body- 50 through a rockable bearing 54. The bearing64 is formed bycomplemental bearing sections 64 and 64 rockably mounted in curved bearing recesses of the pump The impeller 52 is oscillatatably driven by the shaft 37 in a clockwise direction as indicated by the arrow 65 and divides the cylinder 51 into pump chambers comprising an intakechamber 66 and a pressure or discharge chamber 67; The pump body is provided with an intake passage 69 which communicates with the intake chamber 66 and includes an axially extending cylindrical passage portion 70. The passage portion 70 is in an axiallyaligned and communicating relation with the suction passage 42 of the mufiier member 49' and is provided with a suitable screen 71.

The pump body Si? is also provided with one or more radial discharge passages ,72 which communicate with the discharge chamber 67 and connect the latter With a pocket 73 formed between a peripheral portion of the pump body and a curved cover member 74- secured to the latter by connecting screws 75. The discharge pocket 73 is in open communication with the delivery passage 43 of the muffler member 41 as shown in FIGS. 2 and 3, but the communication between the pocket 73 and the discharge chamber 67 is controlled by a suitable check valve device 76. The check valve 76 is here shown as comprising a flexible-blade type of valve member 78 overlying the discharge passage or passages 72 of the pump body and retained in position by a plate 7% secured to the latter by one or more attaching screws. 843. The retaining plate '79 is provided with a curved relief or recess 31 in the inner side thereof to accommodate the valveopening flexing movement of the valve member '78.

The upper and lower end walls of the pump cylinder 51 are formed by the adjacent sides of the motor-frame 33 and the mother member 48, or preferably, by transverse interposed upper and lower liner plates 83 and $4. The liner plate 33 is disposed between the lower end of the motor frame 33and the upper end-of the pump body St The liner plate 84 is. disposed between the upper end of the mutfier member 44 and the lower end of the pump body 50. The mutller member 4% and the pump body 50 are secured together and in a connected relation to the motor frame 33, with the liner plates 83 and 34 in the interposed relation mentioned above, by suitable through clamping bolts or studs 85 extending axially through these members.

The muffler member 40 is provided in the underside thereof with a plurality of recesses, in this instance four such recesses, and the cover member 41 is provided in the upper side thereof with a similar number of similarly arranged recesses which co-operate with the recesses of the muffler member to form a groupof mufiier chambers or pockets 8.7, 88, 89 and 9d. 3 The cover member 41 is secured to the muffler member 40 in this pocket-formpockets.

ing relation as, by means of suitable connecting screws 91. In the group of muffler pockets just described above,

the pockets 87 and 38 are intake or suction fluid pockets, and the pockets $9 and tlare discharge or pumped fluid As shown in FIGS. 2 and 5 of the drawings, the fluid supply passage in the lower end of the assembly 14 is formed by the axial passage 30. of the fitting 17 and the inner end of the recess 44, and communicates with the intake pocket 87 through aradia'lly extending connecting passage 93 formed in the cover member 41. The pockets 87 and 88 are in communication with each other through a connecting passage defined by a notch 94 formed in the upright partition wall 95 which separates these pockets. The intake pocket 88 is in direct communication with the intake passage 69 of the pump 20 through the above-mentioned suction passage 42 of the muffler member 40 and the axial passage. 70 of the pump body 50. The. intake pockets 87, 88 are isolated from the discharge pockets 89, by partition walls 96 and 97 extending between these groups of pockets.

The discharge pocket 3-9 is in open communication with the discharge pocket 73 of the pump 20 through the above-mentioned delivery passage 43 of the muffler member 40 and is also in direct communication with the discharge pocket 90 through a connecting passage formed by a notch 98 provided in the partition wall 99.

From the arrangement of the fluid passages and muflier pockets described above, it will now be understood that fluid returning to the compressor unit from the external pressure fluid circuit through the return portion 18 will enter the housing 11 through the passages 30 and 93 and will move in succession through the intake pockets 37 and 88. The suction fluid will flow upwardly from the pocket 88 through the passages 42 and 70 and will enter the intake chamber 66 of the pump through the intake passage as. The fluid delivery from the pressure "chamber 67 of the pump will move past the check valve member 78 into the pocket 73 and will then be delivered downwardly through the delivery passage 43 and will pass idsuccession through the pockets 8? and 90. The pumped fluid being thus supplied under pressure to the discharge pocket 90 passes from the latter into the main chamber 21 of the housing 11 from which it is supplied to the external fluid circuit through the outlet 15.

In accordance with a further feature of this invention, the pressure fluid being delivered by the pump 20 is passed through the body of liquid 27in direct contact therewith so that the heat of compression contained in the pressure fluid will be, to a large extent, transferred to the liquid. For this purpose the lower end of the assembly 14, in this case the cover member 41 of the muffler, is provided with pressure fluid discharge openings 100 located in a submerged relation in the liquid. These discharge openings 100 are here shown as comprising a row of such openings formed in the bottom of the cover member 41 adjacent the outer side wall of the pocket 90 and located relatively remote from the suction -passage 42. The pumped fluid being delivered through the discharge openings 10 bubbles upwardly through the liquid 27 into the main chamber 21 of the housing 11. The number, size and spacing of the holes 100 is such that the pumped fluid being delivered therethrough' will be broken up into a number of relatively small streams in a spacedapart relation providing good heat-transfer contact with the liquid 27, and so that the bubbling of the pumped fluid through the liquid will be relatively noiseless and will take place with an entrainment of only a minimum amount of oil.

In accordance with stillanother feature of this invention, the unit 10 is provided with novel bypass means between the intake side and the discharge side of the pump 20. This bypass means includes an automatic bypass valve device 102 located within the sealed chamber 21 and having a valve chamber 103 defined by co-operating portions of the mufiler and cover members 40 and 41. This bypass means is also formed in part by a connecting passage 104 provided in the cover member 41 and xtending between the discharge pocket 90 and the lower end of the valve chamber 103, and in 'pant by a connecting passage 105 formedby a cut-away pontion or slot of the member 40 and connecting the lower end of the valve chamber directly with the intakepocket 87. For a purpose which will appear hereinafter, the connecting passage 104 is of a relatively small or restricted crosssectional area. I

The valve device 102 com-prises an annular valve seat 106 located in the chamber 103 in surrounding relation to the upper end of the connecting passage 104 and a valve member 107 in the form of a plunger slidable in the valve chamber and coo-perating with the valve seat. The valve member 107 is here shown as having a lower end 107 of reduced size which engages the valve seat 106.

The valve member 107 includes a valve stem 108 extending upwardly into a spring chamber 109 provided in the pump body 50. The valve stem 108 has a threaded portion carrying a nut 110 which forms an adjustable spring seat for a compression spring 112 located in the chamber 109 in a surrounding relation to the valve stem.

The opposite or inner end of the spring 112 is in engagement with a spring seat 113 formed by the lower end wall of the spring chamber 109. The stem 108 extends through the wall forming the spring seat 113 and through an axial passage 114 thereof which is of a size to provide open fluid pressure communication between the main chamber 21 of the housing 11 and the upper end of the valve chamber 103.

The valve device 102 functions as a bypass valve for controlling the bypass means connecting the intake and discharge sides of the pump 20 but differs from conventional pump bypass valves in important respects, one of which is that this valve device has an initially open position and is closed by a preponderance of pump delivery pressure, whereas the usual pump bypass valve has an initially closed position and is opened by an increase in the discharge pressure of the pump. In this bypass valve 102 the spring 112 is effective on the valve member 107 through the stem 108 to bias the valve member away from the seat 106 and to such initially open position.

From the construction and arrangement of the valve device 102'as above described, it will be recognized that the upper end of the valve member 107 is always subject to the fluid pressure existing in the main chamber 21 and, accordingly, when the pressure in this chamber is built up by the operation of the pump 20 to a value where the load imposed on the upper end of the valve member overcomes the spring 112, the valve member will be moved to its closed position against the seat 106 to thereby close the bypass. Conversely, when the pump 20 is stopped and the fluid pressure in the chamber 21 decreases to apoint where the-spring 112 overcomes the fluid pressure loading of the valve member 107, the spring will then cause opening of the valve member and equalization of fluid pressures between the discharge and intake sides takes place to thereby unload the unit 10 so that restarting of the electric motor 19 can be easily accomplished.

It can be advantageously explained at this point that the fluid being handled by the pump 20 is mainly a gaseous fluid, such as a conventional form of refrigerant, which is readily convertible from a liquid state to a gaseous state by a sudden decrease in pressure or by a heating thereof. When the refrigerant is in its liquid state, it becomes mixed with the lubricant supply provided in the housing 11 so that the body of liquid 27 in the reservoir 26 comprises a mixture of lubricant and refrigerant as previously mentioned above.

One of the problems encountered in the start-up of a compressor unit of the sealed-type containing a body of liquid comprising such a mixture of lubricant and refrigerant is that the compressor is slow inbuilding up the pressure of the pumped fluid to the value needed by the external fluid circuit because of a lack of refrigerant in vapor form at the intake side of. the compressor. This invention overcomes this problem and disadvantage by producing a rapid warm-up-of the unit 10, and particularly of the body of liquid 27, by which the refrigerant component of such body is sufliciently vaporized to provide an adequate supply of intake fluid for the pump 20 to enable the latter to produce a rapid build-up of pressure in the chamber 21. This rapid Warm-up of the unit 10 results primmily from-the discharge of the pumped fluid into the body of liquid 27, in direct contact therewith, through the discharge openings as described above.

Another advantage obtained from the discharge of the pumped fluid into the body of liquid 27 in the manner hereinabove disclosed, and from the immersion of the muflier and cover members 40 and 41 in such body of liquid, is that a good heat-transfer relationship is thus provided between the refrigerant fluid and the liquid body for both the compressed fluid being discharged by the pump 20 and the fluid returning from the external circuit. Moreover, the liquid 27 is in direct contact with a lmge area of the shell of the housing 11. These heattransfer relationships cause heat to be readily dissipated by the unit it). Thus the heat being brought to the unit it) by the fluid returning thereto from the external cir-- cuit, is more readily transferred to the body of liquid 27 and thence to the housing 11 for release by the latter tothe surrounding medium or atmosphere, and accordingly, the condenser of the external circuit can be of a smaller size and lower cost.

A further important advantage obtained in the unit 19 from the rapid warm-up characteristic thereof is that no excessive amount of lubricating oil will pass through the pump it} in an entrained relation in the refrigerant fluid being handled. Such entrained lubricant carried out of the housing 11 with the pumped fluid through the delivery outlet 15 is objectionable because it hampers the proper performance of the refrigerant fluid in the external fluid circuit. This advantage of minimizing the amount of lubricant passing through the pump Ed is obtained in part in the unit by the functioning of the bypass valve 102.

To explain this characteristic or feature of the unit 10, it is pointed out that in general when the compressor of a sealed-type compressor unit is stopped, the pressure fluid tends to leak slowly in a backward direction through the compressor and, in so doing, will cause lubricating oil from the reservoir to be carried into the pump through V, the discharge passage thereof. When a compressor unit subject to this disadvantage is restarted, there is a possibility of damage to the compressor as well as the likelihood that a considerable amount of lubricating oil will be delivered by the unit into the external fluid circuit.

In the compressor unit it however, the bypass "alve 102 opens automatically simultaneously with or shortly after the stopping of the motor 1% and remains open until a predetermined pressure of 'pumpedfluid has again been built up in the chamber 21. This prompt opening of the bypass valve 102 upon stopping of the motor 19, equalizes the fluid pressures between the intake and discharge sides of the pump 2%, thereby eliminating any tendency for leak-back of pumped fluid through the pump such as would tend to carry lubricating oil into the latter.

In the external fluid circuit with which the compressor unit 10 is used, the supply portion 16 represents the high pressure side of the external circuit and thereturn portion 18 represents the lower pressure side thereof.

relation to the upper annular edge 118 of the head of the head of thefittingl7 as a valve seat. When provided in this relation, the check valve member 117 will readily permit fluid returning from the external circuit to enter the intake pocket '87 by lifting the valve member relative to the seat 118 but any preponderance of fiuid pressure inthe housing 11 over that existing in the return portion 18 will move the check valve member to its closed position against the seat 118 and thereby prevent lubricating oil from the body 27 from being carried back into the external circuit. Ordinarily the bypass valve Hi2 will open promptly upon the stopping of the motor 19 to equalize the pressures in the outlet and the return portion 18, as explained above, but if such opening of the bypass valve is delayed or does not take place the check valve 117 will prevent the undesirable carry-back of lubricating oil into the external circuit.

Another important advantage obtained in the compressor unit 10 and produced primarily by the bypass valvedevice 102 thereof is the prevention or elimination of excessive frosting or freeze-up of the evaporator of the external fluid circuit or refrigerant system with which the unit is being used. in this connection it should be explained first that it is a common occurrence in many compressor-condenser-evaporator refrigerant systems that the evaporator becomes heavily frosted with the result that the insulating effect of the frost retards the transfer of heat to the evaporator from the space being cooled thereby. Conventional compressor units operating under these circumstances continue to function but operate inefiiciently and do not satisfactorily accomplish their intended purpose. 7

When the compressor unit It) encounters such a frosted conditionof the evaporator of the external circuit, a

change in the functioning of the unit occurs as the result of the action of the bypass valve 162. Thus, when such a frosted condition of the evaporator has occurred, the fluid returning to the unit 10 through the portion 18 will be abnormally high and will cool the unit and particularly the body of liquid 2"! in the reservoir thereof. This cooled condition results in a reduction in the amount of refrigerant vapor available at the intake of the pump 20 and a consequent decrease in the pressure of the pumped fluid being delivered into the chamber 21.

The decreased, pressure condition thus resulting in the chamber 21 will permit the valve member 167 of the bypass valve 102 to be opened by the spring 112, whereupon the bypass meansbecomes effective to return pumped fluid to the intake side-of the pump. The operation of the pump 20 under these circumstances causes the delivery of pumped fluid to the external circuit through the outlet 15 ,to be greatly reduced or interrupted, and consequently, the expanded refrigerant being supplied to the evaporator will be reduced or interrupted and the evaporator will become defrosted. By the time that the evaporator has been thus defrosted, the local circulation of pumped fluid within the unit it through the bypass valve 102 thereof will result in heating of the .unit and a consequent increase in the amount of refrigerant vapor being supplied to the intake of the pump 20, whereupon, the pressure of pumped fluid in the chamber 21 will again build up and cause an automatic closing of the bypass valve. The unit 10 will thereupon operate with a suflicient pressure in the chamber 21 to cause the required amount of pressure fluid to be supplied .to the external circuit and the evaporator will again perform its normal cooling function.

In connection with this functioning of the unit 10 and the bypass valve 102 thereof to produce such an automatic defrosting of the evaporator, it should be explained that an important relationship existing between the fluid pressures of the intake and discharge of the pump 20 is made use of, namely, that the pressure of the pumped fluid always bears a definite relation to the pressure of the intake or suction fluid. The pressure of the suction fluid in the pump intake is often referred toas back-pressure and, in accordance with the existing pressurerelationship re ferred to just above, any pressure changes in the back pressure of the pump 20 will result in corresponding definite changes in the discharge pressure of the pumped fluid being delivered by the pump. Therefore, by constructing the bypass valve 102 so that the characteristics thereof suit the needs of the unit 10 with respect to the defrosting requirements of the evaporator of the external circuit, automatic opening and closing of the check valve for the accomplishment of such defrosting can be reliably obtained.

In the bypass valve 102 the valve member 107 is a pressure differential responsive member whose automatic movements to open and closed positions for the purposes explained above are obtained by properly selecting the characteristics of the spring 112 and the area of the valve member 167 which is exposed to the fluid pressure of the chamber 21. With respect to the bypass passage 104' which was referred to above as being of a restricted crosssectional area, it is pointed out that the area of this passage is selected to suit the requirements of the unit and is such that an appropriate back pressure will always be maintained on the suction side of the pump 20 to enable the latter to produce a build-up of pressure in the chamber 21. In other words, the cross-sectional area of the passage 104 is restricted sufiiciently to prevent all of the discharge of the pump from passing therethrough.

FIG. 11 of the drawings illustrates one form of refrigerant system 120 in which the compressor unit 10 can be used and in which the compressor unit is shown in a connected relation. The refrigerant system 120 includes a conventional form of condenser 122 which is connected with the outlet 15 of the compressor unit 10, and an evaporator 123 which is connected with the inlet fitting 17 of the unit. The connection of the condenser 122 with the unit 10 is through a conduit extension 124 of the supply portion 16 of the external circuit and the evaporator 123 is connected with the fitting 17 by a conduit extension 125 of the return portion 18. The refrigerant system 120 also includes a capillary tube connection 126 extending between the condenser 122 and the evaporator 123 and through which the expansion of the pressurized refrigerant fluid takes place. i

The illustration of the compressor unit in the refrigerant system 120 of FIG. 11 is diagrammatic in form but corresponds generally'with the compressor unit 10 illust'rated in FIGS. 1 to 7 inclusive and described above, and accordingly, the same reference characters have been applied to the same corresponding parts. Since FIG. 11 is diagrammatic, however, and the bypass valve 102 is shown on a larger scale and in a position outside of the assembly 14, the portions of the bypass means extending to and from the bypass valve and corresponding with the passages above-mentioned 104 and 105 are shown as being the passage of conduits 104 and 105 The passage 104 of the conduit 104- is of the restricted cross-sectional area described above;

In other respects the compressor unit 10 shown in the refrigerant system 120 corresponds, as to the construction and functioning thereof, with the description given above and applying to FIGS. 1 to 7 inclusive with the exception that the check valve .117 has been omitted. When the refrigerant system is of the type which includes a capillary tube as the expansion device thereof, such as the capillary tube 126 of the system 120, the check valve 117 is not needed inasmuch as an equalization of pressures between the condenser 122 and the evaporator 123 will take place through the capillary tube at a sufliciently rapid rate, upon stopping of the driving motor 19, to prevent a carry-back of lubricating oil into the evaporator through the return conduit 125.

FIG. 12 of the drawings shows another form of refrigerant system 130 in which the compressor unit 10is used in the same general relation as in the refrigerant system of FIG. 11 but in which a conventional expansion valve device 132- is used in the conduit 133 means conmeeting the condenser 122 with the evaporator 123. The refrigerant system 130 also differs from the system 120 in that it includes a receiver in the form of'a tank 135 located in the conduit means 133 at a point between the condenser 122 and theexpansion valve 132. 'The system 130 differs further from the system 120 in that the pressure inlet passage 10 3 to the valve chamber 103 of the bypass valve 102 is in open communication with the main chamber 21 of the housing 11 instead of being connected with the discharge pocket 90, as is the case in FIG. 11 and in the compressor unit 10 as described above in connection with FIGS. 1 to 7 inclusive. The passage 104 is of the restricted cross-sectional area described above for the passage 104. a i 1 g The refrigerant system 130, as illustrated in FIG. 12, includes the check valve member 117 in the relation illustrated in FIG. 2 and previously described above. When the refrigerant system includes an expansion valve between the condenser 122 and evaporator 123, such as the expansion valve 132 of the system 130, this check valve is needed to prevent the above-mentioned carry-back of refrigerating oil into the evaporator through the return conduit 125.

The expansion valve 132, which was referred to above as being of a conventional form, includes a movable metering valve member 1136 actuatable toward its closed or restricting position relative to a valve seat member 137 by a diaphragm 138. This diaphragm is subject'to the expansive action of a confined liquid of a conventional thermostat member or bulb 139. The member 139 is located at any suitable point, such as adjacent the return conduit 125 so as to be responsive totemperature changes of the latter, and is connected with the diaphragm chamber by a conduit 141. When the bypass valve 102 has the pressure fluid inlet passage 104lthereof in open communication with the main chamber 21 of the housing 11 as shown in FIG. 12, the fluid being bypassed from the discharge side to the intake side of the pump 20 will also pass through the body of liquid 27 and will result in additional heating of the liquid by the heat of compression contained in that portion of the pumped fluid which moves through the bypass means.

With respect to the valve device 102, it will be recognized from the construction thereof shown in thedrawings and the functioning thereof as an unloading and bypass valve as described above, that by reason of the action of the spring 112 on the valve member 107 in conjunction with variable fluid pressure values also acting thereon, this valve device will operate with a modulating action related to the operation of the pump 20 and thefunctioning of the refrigerating system in general.

Reverting to the construction of the pump 20 and to I i the variable capacity feature thereof, reference will now be made to FIGS. 8, 9 and 10 of the drawings. These views are diagrammatic in form but otherwise correspond with the construction of the pump 20 as illustrated in FIGS. 1 to 7 inclusive and described above, and the same reference characters have been applied to the same corresponding parts. Ineach of the diagrams of FIGS. 8, 9

r and 10, the rotation axis of the shaft 37 is designated by the reference numeral 60 and is also the transverse axis or center line of the. pump cylinder. 51. The offset relation or eccentricity of the pump eccentric 53 relative to the rotation axis 60 is represented by the dimensional distance 145.

The impeller 54- and the adapter 56 have a common true center 146 which is shown in FIGS. 8, 9 and 10 as lying on a transverse center line 147. The truecenter of the shaft eccentric 53, indicated by the reference nushaft eccentric 53 and the adapter 56, will represent the effective throw of the shaft 37 for producing the gyratory' tangential movement of the impeller 52 in the cylinder 51. This combined eccentricity or throw is represented in FIG. 8 by the dimensional distance 153 and is the actual or arithmetical sum of the two eccentricities and 152.

In accordance with the present invention, the adapter 56 and the impeller 52 are constructed so that the adapter can be assembled in the impeller opening 55 in any desired angular or rotative position therein. For this purpose the adapter 56 preferably has a press fit in the impeller 52 and, when thus assembled therein, is relatively nonrotatable. I

To achieve the volumetric capacity rating desired or 1 1 specified for the pump 20, the cylinder 51 is bored in the pump body 56 to a specified diameter, such that when the adapter 56 is assembled in the impeller 52 in the angular relation to produce a combined or resultant eccentricity which will give the shaft 37 a throw of a dimensional value equalto that needed for gyrating the impeller 52 in the cylinder 51 with a maintained tangential engagement 52 therebetween, the capacities of the pump chambers 66 and 67 on opposite sides of the abutment vane 61 will be such as to provide the desired or specified output rating of the pump. It will accordingly be seen that a pump of the desired output rating can be readily provided by merely boring out the pump body 50 to the diameter specified for the cylinder 51 and assembling the adapter 56 in the impeller 52 in the proper angular or rotative position therein.

This construction and assembly procedure for the pump 20 makes it possible to obtain the desired capacity rating without stocking a large number of component pants of various different sizes. Thus, the pump body 56 can be a standard-size casting in which a cylinder 51 of the appropriate diameter can be bored. The impeller 52, as well as the shaft 3 7 and the adapter 56, can all be standardized parts which will be of the same dimensions for a series of pumps of different output capacity ratings. When the pump body 51) has been bored out to the appropriate. cylinder size, it is then only necessary to assemble the adapter 56 in the proper angular relation in the impeller opening 55 to provide the shaft 37 with a throw 26* represents one extreme value of pump output rating which is obtainable from the eccentricity values 145 and 152, inasmuch as the throw of the shaft 37 in this view corresponds with the sum of these eccentricities and is the maximum value obtainable from the particular pump eccentric 53 and the particular adapter 56 shown.

v FIG. 9 of the drawings represents the other extreme of output capacity rating obtainable for a pump 26 from the particular pump eccentric 53 and the particular adap-ter 56. In FIG. 9 the rotative position in which the adapter 56 has been assembled in the impeller 52 is different from that of FIG. 8 and is a position in which the throw of the shaft 37 is the resultant eccentricity represented by the dimensional value 155 and is a minimum throw value obtainable from the particular pump eccentric 53 and the particular adapter 56. From a comparison of FIG. 9 with FIG. 8 it will thus be seen that this resultant eccentricity 155 is the arithmetical diiference between the eccentricities 152 and 145.

For use in-the pump 20* of FIG. 9, the cylinder 51 is formed in the standard pump body 50 by boring out the latter to a smaller diameter than for the pump'2ti shown in FIG. 8 and to a diameter appropriate for the minimumvalue throw represented by the resultant or combined eccentricity 155. The pump 20* of FIG. 9 therefore has pump chambers. 66? and 67 of. a reduced volumetric capacity as compared with the corresponding pump chambers 66 and 67 of FIG. 8. v f

FIG. 10 of the drawings shows a pump 211 of an intermediate capacity rating and assembled from the same pump components as in FIGS. 8 and 9 but with the adapter 56 rotatively positioned in the impeller 52 at an inter mediate angular setting, in this instance, a setting corresponding with a 45 degree rotative adjustment. When the adapter 56 is assembled in this position, the resultant eccentricity is an intermediate value as represented by the dimensional distance 157 and provides a throw of an intermediate value for the shaft 37. The pump body 50 of FIG. 10 is bored out so as to provide therein a cylinder 51 whose diameter is of an intermediate dimensional value as compared with the cylinders of FIGS. 8 and 9.

Thus, FIGS. 8 and 9 represent two extreme assembly relationships for the pump components to provide pumps 29 and 20* having desired maximum and minimum discharge capacity ratings, and FIG. 10 represents an assembly relationship in a pump 20 for achieving one intermediate discharge capacity rating. Various other inter. mediate discharge capacity ratings are obtainable from the samepump components by merely varying the angular position for the adapter 56 and correspondingly varying the diameter of the cylinder bore being formed in the pump body, to suit the throw obtained from the particular assembly position of the adapter. By providing the construction shown and described for the pump 20, it will accordingly be seen that any desired capacity rating can be obtained within the maximum limits for which the components have been designed, and accordingly, it will only be necessary to stock a minimum number of pump parts.

For lubricating the main pump 20 and other moving parts, the compressor unit 10 is also provided with an oil pump 160 having a suction passage 161 for picking up lubricant from the liquid body 27 and a discharge passage 162 for delivering the lubricant under pressure. The oil pump 161i is here shown as being of the rotary type having an impeller 163 formed by an eccentric portion of the shaft 37 and a vane-type abutment member 164 cooperating with such impeller.

The cylinder 165 of the oil pump is formed by a portion of the bore of the muffler member 40' and the abutment vane 164 is slidable in a radial slot of the latter and is pressed against the impeller 163 by a compression spring 166. The pump 160 has intake and discharge passages 168 and 169 located on opposite sides of the abutment vane 164 and which communicate respectively with the suction passage 161 and the oil delivery passage 162.

The suction passage 161 is an axial passage located near the; shaft'37 so that the lower end of this passage will communicate with the reservoir 26 at the deepest part thereof and at a point remote from the discharge passages 160. This location for the suction passage 161 insures a solid and adequate supply of lubricant for the oil pump 160 at all times.

- The delivery passage 162 supplies oil under pressurev to a radial distribution passage 171 from which the oil is suitably fed to the moving parts of the main pump20 with more or less oil passing through the pump and into an axial passage 172 which is formed in the motor frame 33 and supplies lubricant to the hollow shaft bearing 36. The lower end of the shaft 37 is provided with aflat thrust face which co-operates with a thrust bearing surface 173 provided on the cover member 41. A radial oil distribution passage 174 receives oil from the discharge passage 162 for lubricating this thrust bearing surface.

,From the accompanying drawings and the foregoingdetailed description it will now be readily understood that this invention provides a compressor unit of a simple and highly practical form and which achieves many important advantages from the standpoint of operational performance as well as from the standpoint of construction, as-

sembly procedure, and number of component parts required to be stocked. Since these various advantages have been largely'explained hereinabove, they need not be further summarized at this point.

. Although the compressor unit of this invention has been illustrated and described herein to a somewhat detailed extent it will be understood, of course, that the invention is not to be regarded as being limited correspondingly in scope but includes all changes and-modifications coming and connected with said compressor and containing sue-- tion fluid chamber means communicating with said intake passage, and pumped-fluid chamber means communicatmeans also having a bypass passage therein connecting said pumped-fluid chamber means with said suction fluid ing with said single delivery passage for receiving therefrom the entire compressor output of pumped fluid; said mufller means being in heat-exchange contact with said body of oil for transfer of heat to the oil and having discharge opening means leading from said pumped-fluid chamber means and located in a submerged relation to said body of oil for passing said entire compressor output of pumped fluid through said oil in direct contact therewith for a further transfer of heat to the oil.

2. In a compressor unit, a sealed housing having a pressure fluid delivery outlet and also having a reservoir adapted to contain a body of lubricating oil, a compressor in said housing and having an intake passage for suction fluid and a single delivery passage for pumped fluid, a motor in said housing and connected with said compressor for driving the same, hollow mufller means in said housing in heat-exchange contact with said body of oil and located to receive the entire compressor output of pumped fluid from said delivery passage and having discharge opening means in a submerged relation to oil contained in said reservoir for passing said entire compressor output of pumped fluid through said oil in direct contact therewith, means insaid housing providing a bypass for connecting said discharge passage with said intake passage, and automatic valve means in said housing controlling said bypass and having an initially open position at start-up of said unit for bypassing fluid to said intake passage.

3. In a compressor unit for use in a compressor-condenser-evaporator refrigerant circuit having fluid supply and return portions, a sealed housing having a pressure fluid delivery outlet adapted to be connected with the supply portion of said circuit and also having a reservoir containing a body of lubricating oil, a compressor in said housing and having an intake passage for connection with said return portion and a single delivery passage, a motor in said housing and connected with said compressor for driving the same, refrigerant in said circuit and in said housing in contact with said oil and comprising a liquid subject to at least a partial gasification in response to increase in the temperature thereof, hollow muffler means in said housing in heat-exchange contact with said oil and located to receive the entire compressor output of pumped fluid from said delivery passage, said muffler means having discharge opening means in a submerged relation to said oil for passing said entire compressor output of pumped fluid through the oil in direct contact therewith, means in said housing providing a bypass for connecting said discharge passage with said intake passage, and pressure differential responsive automatic valve means in said housing controlling said bypass and operable in response to a predetermined pressure diflerential between intake passage fluid anddischarge passage fluid for closing said bypass, said valve means having an initially open position for bypassing refrigerant to facilitate start-up of the unit.

4. In a compressor unit; a sealed housing having a pressure fluid delivery outlet, and also having a reservoir in the lower portion thereof adapted to contain a body of lubricating oil; a compressor in said housing and having an intake passage for suction fluid and a single delivery passage for pumped fluid; a motor in said housing and located above and connected with said compressor for driving the latter; hollow muflier means in said housing in a position below and connected with said compressor and containing suction fluid chamber means communicating with said intake passage, and pumped-fluid chamber means communicating with said delivery passage for receiving therefrom the entire compressor output of pumped fluid; said muffler means having discharge opening means leading from said pumped-fluid chamber means and located in a submerged relation to oil contained in said reservoir for passing said entire compressor output of pumped fluid through said oil in direct contact therewith; said muffler chamber means; and pressure'differential responsive automatic valve means in said housing controllingsaid bypass passage and operable in response to a predetermined pressure differential between pumped fluid pressure and suction fluid pressure for closing said bypass passage; said valve means comprising a valve member having an 'initially open position for bypassing pumped fluid through said bypass passage to facilitate start-up of the unit, and spring means biasing said valve member toward said initially open position.

5. In a compressor unit for use in a compressor-condenser-evaporator refrigerant circuit having fluid supply and return portions, a sealed housing having a pressure fluid delivery outlet and also having a reservoir containing a body of lubricating oil, a compressor in said housing and having an intake passage for connection with said return portion-and a single delivery passage for connection with said supply portion, a motor in said housing and connected with said compressor for driving the same, refrigerant in said circuit and in said housing in contact with said oil and comprising a liquid subject to at least a partial gasification in response to increase in the temperature thereof, hollow muffler means'in said housing in heat-exchange contact with said oil and located to receive the entire compressor output of pumped fluid from said delivery passage, said mufller means having discharge I opening means in a submerged relation to said oil for passing said entire compressor output of pumped fluid through the oil in direct contact therewith, means in said housing providing a bypass for connecting said discharge passage with said intake passage, pressure differential responsive automatic valve means in said housing controlling said bypass and operable in response to a predetermined pressure differential between intake passage fluid and discharge passage fluid for closing said bypass, said valve means having an initially open position for bypassing refrigerant to facilitate start-up of the unit and spring means for urging thevalve means to said initially open position, and check valve means controlling communication between said return portion and said intake passage and openable toward the latter.

6. In a compressor unit for use in a compressor-condenser-evaporator refrigerant circuit having fluid supply and return portions; a substantially closed housing; a compressor in said housing and having an intake passage for suction fluid and a single discharge passage for pumped fluid; a motor in said housing above said compressor and drivingly connected with the latter; said housing having a liquid collecting'reservoir in the lower portion thereof; refrigerant in, said circuit including a body of liquid in said reservoir comprising a mixture of lubricant and a liquid refrigerant subject to at least a partial gasification in response to heating of said body of liquid; mufiler means in said housing below said compressor so as to be in heatexchange contact with said body of liquid and containing intake chambers in a series fluid-circuit relation and connecting said return portion with said intake passage; said mufller means also containing discharge chambers in a series fluid-circuit relation and with one of said discharge chambers being connected with said discharge passage for receiving therefrom the entire compressor output of pumped fluid, and another of said discharge chambers having discharge opening means in a submerged relation in said body of liquid for discharging said entire compressor output of pumped fluidinto the body of liquid in direct contact therewith; means in said housing providmg a bypass connecting one of said intake chambers with one of said discharge chambers and including a valve chamber in said muffler means; a pressure difierential responsive valve member controlling said bypass and operable in said valve chamber in response to a predetermined pressure differential between the intake and discharge chambers connected'by said bypass; and spring 1.5 means tending to move said valve member to an open position for unloading said compressor through said bypass upon stopping of said power means and for bypassing fiuid from said discharge passage to said intake passage to facilitate start-up of said power means and cause heating of said body of liquid.

7; A compressor unit as defined in claim 1 wherein said hollow muifier means comprises a muffler member containing an annular group of chambers certain of which comprise said suction chamber means and others of which comprise said pumped-fluid chamber means; said mufiier member having a wall portion disposed in a submerged relation in said oil and provided with a group of spaced V 16 holes for discharging said entire compressor output of pumped fluid directly into the oil from said pumpedfluid chamber means as a plurality of individual streams.

References fited in the file of this patent UNITED STATES PATENTS 

